These drugs can cost more than $100,000 a year for patients with CML, once considered a death sentence but now highly treatable with ongoing treatment, according to a commentary penned by 120 specialists in more than 15 countries and published online April 25 in the journal Blood.

"Patients with CML have a much better outlook today than ever before, thanks to advances that have greatly improved survival rates. But these patients now face dire financial struggles as they try to maintain their treatment regimen with the drastically inflating cost of care," corresponding author Dr. Hagop Kantarjian, chairman of the leukemia department at the University of Texas MD Anderson Cancer Center in Houston, said in a journal news release.

"Since CML treatments must be taken on an ongoing basis, we are concerned that the surging prices are potentially harming patients," Kantarjian added.

In the United States, the CML survival rate is about 60 percent, significantly less than in Sweden, where survival odds are roughly 80 percent. That's likely because drug costs are managed in Sweden, the doctors noted.

Patients with other types of cancer who require ongoing treatment likely face the same barrier to treatment, Kantarjian added.

Eleven of 12 cancer drugs approved by the U.S. Food and Drug Administration in 2012 were priced above $100,000 a year, the report noted. And average monthly cancer drug prices have nearly doubled over the past decade -- from $5,000 a month to more than $10,000 a month, according to the news release.

Moreover, cancer care is a key factor in the massive cost of health care in the United States, estimated at 18 percent of the U.S. Gross Domestic Product, compared with less than 10 percent in much of Europe, the researchers added.

The drugs for CML include Gleevec from Novartis; Pfizer Inc.'s Bosulif; Sprycel from Bristol-Myers Squibb and Synribo from Teva.

How prices are set lies at the heart of the issue, according to the experts.

"In many cases, it makes sense to let the market govern the price; however, when a product is directly related to a patient's survival over a period of years, it is critical to set a price that allows companies to profit and ensures that patients can afford their treatment," said Kantarjian.

Drug makers argue that the stratospheric prices reflect the cost of research and development and the "value of a drug to patients," according to the New York Times.

In the Blood article, the authors noted that the reported cost of bringing a new cancer drug to market is roughly $1 billion, although not all experts agree on that high a figure.

Yet, Gleevec's sales were $4.7 billion in 2012 alone, the Times reported.

Noting the pricing and maintenance issue is "complex," Novartis said in a statement Thursday that it would "welcome the opportunity to be part of the dialogue."

This isn't the first time cancer specialists have banned together to oppose high drug prices, according to the Times. Last fall, doctors at Memorial Sloan-Kettering Cancer Center in New York City announced they wouldn't use the Sanofi colon cancer drug Zaltrap because it cost twice as much as another drug and wasn't an improvement. Subsequently, Sanofi cut the price of the drug in half.